diff options
Diffstat (limited to 'src/arch/x86/syscall.h')
| -rw-r--r-- | src/arch/x86/syscall.h | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/src/arch/x86/syscall.h b/src/arch/x86/syscall.h new file mode 100644 index 0000000..2fb3552 --- /dev/null +++ b/src/arch/x86/syscall.h @@ -0,0 +1,200 @@ +/* SPDX-License-Identifier: MIT */ + +#ifndef LIBURING_ARCH_X86_SYSCALL_H +#define LIBURING_ARCH_X86_SYSCALL_H + +#ifndef LIBURING_SYSCALL_H +# error "This file should be included from src/syscall.h (liburing)" +#endif + +#if defined(__x86_64__) +/** + * Note for syscall registers usage (x86-64): + * - %rax is the syscall number. + * - %rax is also the return value. + * - %rdi is the 1st argument. + * - %rsi is the 2nd argument. + * - %rdx is the 3rd argument. + * - %r10 is the 4th argument (**yes it's %r10, not %rcx!**). + * - %r8 is the 5th argument. + * - %r9 is the 6th argument. + * + * `syscall` instruction will clobber %r11 and %rcx. + * + * After the syscall returns to userspace: + * - %r11 will contain %rflags. + * - %rcx will contain the return address. + * + * IOW, after the syscall returns to userspace: + * %r11 == %rflags and %rcx == %rip. + */ + +static inline void *__arch_impl_mmap(void *addr, size_t length, int prot, + int flags, int fd, off_t offset) +{ + void *rax; + register int r10 __asm__("r10") = flags; + register int r8 __asm__("r8") = fd; + register off_t r9 __asm__("r9") = offset; + + __asm__ volatile( + "syscall" + : "=a"(rax) /* %rax */ + : "a"(__NR_mmap), /* %rax */ + "D"(addr), /* %rdi */ + "S"(length), /* %rsi */ + "d"(prot), /* %rdx */ + "r"(r10), /* %r10 */ + "r"(r8), /* %r8 */ + "r"(r9) /* %r9 */ + : "memory", "rcx", "r11" + ); + return rax; +} + +static inline int __arch_impl_munmap(void *addr, size_t length) +{ + long rax; + + __asm__ volatile( + "syscall" + : "=a"(rax) /* %rax */ + : "a"(__NR_munmap), /* %rax */ + "D"(addr), /* %rdi */ + "S"(length) /* %rsi */ + : "memory", "rcx", "r11" + ); + return (int) rax; +} + +static inline int __arch_impl_madvise(void *addr, size_t length, int advice) +{ + long rax; + + __asm__ volatile( + "syscall" + : "=a"(rax) /* %rax */ + : "a"(__NR_madvise), /* %rax */ + "D"(addr), /* %rdi */ + "S"(length), /* %rsi */ + "d"(advice) /* %rdx */ + : "memory", "rcx", "r11" + ); + return (int) rax; +} + +static inline int __arch_impl_getrlimit(int resource, struct rlimit *rlim) +{ + long rax; + + __asm__ volatile( + "syscall" + : "=a"(rax) /* %rax */ + : "a"(__NR_getrlimit), /* %rax */ + "D"(resource), /* %rdi */ + "S"(rlim) /* %rsi */ + : "memory", "rcx", "r11" + ); + return (int) rax; +} + +static inline int __arch_impl_setrlimit(int resource, const struct rlimit *rlim) +{ + long rax; + + __asm__ volatile( + "syscall" + : "=a"(rax) /* %rax */ + : "a"(__NR_setrlimit), /* %rax */ + "D"(resource), /* %rdi */ + "S"(rlim) /* %rsi */ + : "memory", "rcx", "r11" + ); + return (int) rax; +} + +static inline int __arch_impl_close(int fd) +{ + long rax; + + __asm__ volatile( + "syscall" + : "=a"(rax) /* %rax */ + : "a"(__NR_close), /* %rax */ + "D"(fd) /* %rdi */ + : "memory", "rcx", "r11" + ); + return (int) rax; +} + +static inline int __arch_impl_io_uring_register(int fd, unsigned opcode, + const void *arg, + unsigned nr_args) +{ + long rax; + register unsigned r10 __asm__("r10") = nr_args; + + __asm__ volatile( + "syscall" + : "=a"(rax) /* %rax */ + : "a"(__NR_io_uring_register), /* %rax */ + "D"(fd), /* %rdi */ + "S"(opcode), /* %rsi */ + "d"(arg), /* %rdx */ + "r"(r10) /* %r10 */ + : "memory", "rcx", "r11" + ); + return (int) rax; +} + +static inline int __arch_impl_io_uring_setup(unsigned entries, + struct io_uring_params *p) +{ + long rax; + + __asm__ volatile( + "syscall" + : "=a"(rax) /* %rax */ + : "a"(__NR_io_uring_setup), /* %rax */ + "D"(entries), /* %rdi */ + "S"(p) /* %rsi */ + : "memory", "rcx", "r11" + ); + return (int) rax; +} + +static inline int __arch_impl_io_uring_enter(int fd, unsigned to_submit, + unsigned min_complete, + unsigned flags, sigset_t *sig, + int sz) +{ + long rax; + register unsigned r10 __asm__("r10") = flags; + register sigset_t *r8 __asm__("r8") = sig; + register int r9 __asm__("r9") = sz; + + __asm__ volatile( + "syscall" + : "=a"(rax) /* %rax */ + : "a"(__NR_io_uring_enter), /* %rax */ + "D"(fd), /* %rdi */ + "S"(to_submit), /* %rsi */ + "d"(min_complete), /* %rdx */ + "r"(r10), /* %r10 */ + "r"(r8), /* %r8 */ + "r"(r9) /* %r9 */ + : "memory", "rcx", "r11" + ); + return (int) rax; +} + +#else /* #if defined(__x86_64__) */ + +/* + * TODO: Add x86 (32-bit) support here. + */ +#error "x86 (32-bit) is currently not supported for nolibc builds" + +#endif /* #if defined(__x86_64__) */ + +#endif /* #ifndef LIBURING_ARCH_X86_SYSCALL_H */ |